"auto" was defined as a keyword back in the K&R days, but as a storage
type specifier. No one ever used it, since it was and is the default
storage type for local variables.
C++11 recycled the keyword to allow a type to be declared based on the
type of an initializer. This was finally adopted into standard C in
C23.
gcc and clang provide the "__auto_type" alias keyword as an extension
for pre-C23, however, there is no reason to pollute the bulk of the
source base with this temporary keyword; instead define "auto" as a
macro unless the compiler is running in C23+ mode.
This macro is added in <linux/compiler_types.h> because that header is
included in some of the tools headers, wheres <linux/compiler.h> is
not as it has a bunch of very kernel-specific things in it.
Changes in v2:
- Restore indentation of macro backslashes (David Laight)
- arch/nios2: Replace an adjacent typeof() with a similar "auto" construct
(Linus Torvalds)
- fs/proc/inode.c: change "__auto_type" to "const auto" (Alexey Dobriyan)
---
arch/nios2/include/asm/uaccess.h | 8 ++++----
arch/x86/include/asm/bug.h | 2 +-
arch/x86/include/asm/string_64.h | 6 +++---
arch/x86/include/asm/uaccess_64.h | 2 +-
fs/proc/inode.c | 16 ++++++++--------
include/linux/cleanup.h | 6 +++---
include/linux/compiler.h | 2 +-
include/linux/compiler_types.h | 13 +++++++++++++
include/linux/minmax.h | 6 +++---
tools/testing/selftests/bpf/prog_tests/socket_helpers.h | 9 +++++++--
tools/virtio/linux/compiler.h | 2 +-
11 files changed, 45 insertions(+), 27 deletions(-)